Creation

1963 photo showing Dr. William H. Pickering, (center) JPL Director, President John F. Kennedy, (right). NASA Administrator James Webb in background. They are discussing the Mariner program, with a model presented.

From 1946, the National Advisory Committee for Aeronautics (NACA) had been experimenting with rocket planes such as the supersonic Bell X-1.[12] In the early 1950s, there was challenge to launch an artificial satellite for the International Geophysical Year (1957–58). An effort for this was the American Project Vanguard. After the Soviet launch of the world's first artificial satellite (Sputnik 1) on October 4, 1957, the attention of the United States turned toward its own fledgling space efforts. The U.S. Congress, alarmed by the perceived threat to national security and technological leadership (known as the "Sputnik crisis"), urged immediate and swift action; President Dwight D. Eisenhower and his advisers counseled more deliberate measures. This led to an agreement that a new federal agency mainly based on NACA was needed to conduct all non-military activity in space. The Advanced Research Projects Agency (ARPA) was created in February 1958 to develop space technology for military application.[13]

Space flight programs

NASA has conducted many manned and unmanned spaceflight programs throughout its history. Unmanned programs launched the first American artificial satellites into Earth orbit for scientific and communications purposes, and sent scientific probes to explore the planets of the solar system, starting with Venus and Mars, and including "grand tours" of the outer planets. Manned programs sent the first Americans into low Earth orbit (LEO), won the Space Race with the Soviet Union by landing twelve men on the Moon from 1969 to 1972 in the Apollo program, developed a semi-reusable LEO Space Shuttle, and developed LEO space station capability by itself and with the cooperation of several other nations including post-Soviet Russia.

Manned programs

The experimental rocket-powered aircraft programs started by NACA were extended by NASA as support for manned spaceflight. This was followed by a one-man space capsule program, and in turn by a two-man capsule program. Reacting to loss of national prestige and security fears caused by early leads in space exploration by the Soviet Union, in 1961 President John F. Kennedy proposed the ambitious goal "of landing a man on the Moon by the end of [the 60s], and returning him safely to the Earth." This goal was met in 1969 by the Apollo program, and NASA planned even more ambitious activities leading to a manned mission to Mars. However, reduction of the perceived threat and changing political priorities almost immediately caused the termination of most of these plans. NASA turned its attention to an Apollo-derived temporary space laboratory, and a semi-reusable Earth orbital shuttle. In the 1990s, funding was approved for NASA to develop a permanent Earth orbital space station in cooperation with the international community, which now included the former rival, post-Soviet Russia. To date, NASA has launched a total of 166 manned space missions on rockets, and thirteen X-15 rocket flights above the USAF definition of spaceflight altitude, 260,000 feet (80 km).[18]

X-15 rocket plane (1959–68)

X-15 in free flight

The X-15 was an NACA experimental rocket-powered hypersonic research aircraft, developed in conjunction with the U.S. Air Force and Navy. The design featured a slender fuselage with fairings along the side containing fuel and early computerized control systems.[19]Requests for proposal were issued on December 30, 1954 for the airframe, and February 4, 1955 for the rocket engine. The airframe contract was awarded to North American Aviation in November 1955, and the XLR30 engine contract was awarded to Reaction Motors in 1956, and three planes were built. The X-15 was drop-launched from the wing of one of two NASA Boeing B-52 Stratofortresses, NB52A tail number 52-003, and NB52B, tail number 52-008 (known as the Balls 8). Release took place at an altitude of about 45,000 feet (14 km) and a speed of about 500 miles per hour (805 km/h).

Twelve pilots were selected for the program from the Air Force, Navy, and NACA (later NASA). One hundred ninety-nine flights were made between 1959 and 1968, resulting in the official world record for the highest speed ever reached by a manned powered aircraft (current as of 2014), and a maximum speed of Mach 6.72, 4,519 miles per hour (7,273 km/h).[20] The altitude record for X-15 was 354,200 feet (107.96 km).[21] Eight of the pilots were awarded Air Force astronaut wings for flying above 260,000 feet (80 km), and two flights by Joseph A. Walker exceeded 100 kilometers (330,000 ft), qualifying as spaceflight according to the International Aeronautical Federation. The X-15 program employed mechanical techniques used in the later manned spaceflight programs, including reaction control system jets for controlling the orientation of a spacecraft, pressurized space suits, and horizon definition for navigation.[21] The reentry and landing data collected were valuable to NASA for designing the Space Shuttle.[19]

Project Mercury (1959–63)

Friendship 7, NASA's first manned orbital spaceflight

Shortly after the Space Race began, an early objective was to get a person into Earth orbit as soon as possible, therefore the simplest spacecraft that could be launched by existing rockets was favored. U.S. Air Force's Man in Space Soonest program looked at many manned spacecraft designs, ranging from rocket planes like the X-15, to small ballistic space capsules.[22] By 1958, the space plane concepts were eliminated in favor of the ballistic capsule.[23]

When NASA was created that same year, the Air Force program was transferred to it and renamed Project Mercury. The first seven astronauts were selected among candidates from the Navy, Air Force and Marine test pilot programs. On May 5, 1961, astronaut Alan Shepard became the first American in space aboard Freedom 7, launched by a Redstone booster on a 15-minute ballistic (suborbital) flight.[24]John Glenn became the first American to be launched into orbit by an Atlas launch vehicle on February 20, 1962 aboard Friendship 7.[25] Glenn completed three orbits, after which three more orbital flights were made, culminating in L. Gordon Cooper's 22-orbit flight Faith 7, May 15–16, 1963.[26]

The Soviet Union (USSR) competed with its own single-pilot spacecraft, Vostok. They beat the U.S. for the first man in space, by launching cosmonaut Yuri Gagarin into a single Earth orbit aboard Vostok 1 in April 1961, one month before Shepard's flight.[27] In August 1962, they achieved an almost four-day record flight with Andriyan Nikolayev aboard Vostok 3, and also conducted a concurrent Vostok 4 mission carrying Pavel Popovich.

Project Gemini (1961–66)

The first rendezvous of two spacecraft, achieved by Gemini 6 and 7

Based on studies to grow the Mercury spacecraft capabilities to long-duration flights, developing [29][30]

Under the direction of Soviet Premier Nikita Khrushchev, the USSR competed with Gemini by converting their Vostok spacecraft into a two- or three-man Voskhod. They succeeded in launching two manned flights before Gemini's first flight, achieving a three-cosmonaut flight in 1963 and the first EVA in 1964. After this, the program was then canceled, and Gemini caught up while spacecraft designer Sergei Korolev developed the Soyuz spacecraft, their answer to Apollo.

Project Apollo (1961–72)

The U.S public's perception of the Soviet lead in putting the first man in space, motivated President John F. Kennedy to ask the Congress on May 25, 1961 to commit the federal government to a program to land a man on the Moon by the end of the 1960s, which effectively launched the Apollo program.[31]

Apollo was one of the most expensive American scientific programs ever. It cost more than $20 billion in 1960s dollars[32] or an estimated $205 billion in present-day US dollars.[33] (In comparison, the Manhattan Project cost roughly $26.2 billion, accounting for inflation.)[33][34] It used the Saturn rockets as launch vehicles, which were far bigger than the rockets built for previous projects.[35] The spacecraft was also bigger; it had two main parts, the combined command and service module (CSM) and the lunar landing module (LM). The LM was to be left on the Moon and only the command module (CM) containing the three astronauts would eventually return to Earth.

Buzz Aldrin on the Moon, 1969

The second manned mission, Apollo 8, brought astronauts for the first time in a flight around the Moon in December 1968.[36] Shortly before, the Soviets had sent an unmanned spacecraft around the Moon.[37] On the next two missions docking maneuvers that were needed for the Moon landing were practiced[38][39] and then finally the Moon landing was made on the Apollo 11 mission in July 1969.[40]

Apollo set major milestones in human spaceflight. It stands alone in sending manned missions beyond low Earth orbit, and landing humans on another celestial body.[43]Apollo 8 was the first manned spacecraft to orbit another celestial body, while Apollo 17 marked the last moonwalk and the last manned mission beyond low Earth orbit to date. The program spurred advances in many areas of technology peripheral to rocketry and manned spaceflight, including avionics, telecommunications, and computers. Apollo sparked interest in many fields of engineering and left many physical facilities and machines developed for the program as landmarks. Many objects and artifacts from the program are on display at various locations throughout the world, notably at the Smithsonian's Air and Space Museums.

Skylab (1965–79)

Skylab space station, 1974

Skylab was the United States' first and only independently built space station.[44] Conceived in 1965 as a workshop to be constructed in space from a spent Saturn IB upper stage, the 169,950 lb (77,088 kg) station was constructed on Earth and launched on May 14, 1973 atop the first two stages of a Saturn V, into a 235-nautical-mile (435 km) orbit inclined at 50° to the equator. Damaged during launch by the loss of its thermal protection and one electricity-generating solar panel, it was repaired to functionality by its first crew. It was occupied for a total of 171 days by 3 successive crews in 1973 and 1974.[44] It included a laboratory for studying the effects of microgravity, and a solar observatory.[44] NASA planned to have a Space Shuttle dock with it, and elevate Skylab to a higher safe altitude, but the Shuttle was not ready for flight before Skylab's re-entry on July 11, 1979.[45]

To save cost, NASA used one of the Saturn V rockets originally earmarked for a canceled Apollo mission to launch the Skylab. Apollo spacecraft were used for transporting astronauts to and from the station. Three three-man crews stayed aboard the station for periods of 28, 59, and 84 days. Skylab's habitable volume was 11,290 cubic feet (320 m3), which was 30.7 times bigger than that of the Apollo Command Module.[45]

Apollo-Soyuz Test Project (1972–75)

Apollo-Soyuz crews with models of spacecraft, 1975

On May 24, 1972, US President Richard M. Nixon and Soviet Premier Alexei Kosygin signed an agreement calling for a joint manned space mission, and declaring intent for all future international manned spacecraft to be capable of docking with each other.[46] This authorized the Apollo-Soyuz Test Project (ASTP), involving the rendezvous and docking in Earth orbit of a surplus Apollo Command/Service Module with a Soyuz spacecraft. The mission took place in July 1975. This was the last US manned space flight until the first orbital flight of the Space Shuttle in April 1981.[47]

The mission included both joint and separate scientific experiments, and provided useful engineering experience for future joint US–Russian space flights, such as the Shuttle–Mir Program[48] and the International Space Station.

Space Shuttle program (1972–2011)

The Space Shuttle became the major focus of NASA in the late 1970s and the 1980s. Planned as a frequently launchable and mostly reusable vehicle, four space shuttle orbiters were built by 1985. The first to launch, Columbia, did so on April 12, 1981,[49] the 20th anniversary of the first space flight by Yuri Gagarin.[50]

Its major components were a spaceplane orbiter with an external fuel tank and two solid-fuel launch rockets at its side. The external tank, which was bigger than the spacecraft itself, was the only component that was not reused. The shuttle could orbit in altitudes of 185–643 km (115–400 miles)[51] and carry a maximum payload (to low orbit) of 24,400 kg (54,000 lb).[52] Missions could last from 5 to 17 days and crews could be from 2 to 8 astronauts.[51]

On 20 missions (1983–98) the Space Shuttle carried Spacelab, designed in cooperation with the European Space Agency (ESA). Spacelab was not designed for independent orbital flight, but remained in the Shuttle's cargo bay as the astronauts entered and left it through an airlock.[53] Another famous series of missions were the launch and later successful repair of the Hubble Space Telescope in 1990 and 1993, respectively.[54]

In 1995, Russian-American interaction resumed with the Shuttle-Mir missions (1995–1998). Once more an American vehicle docked with a Russian craft, this time a full-fledged space station. This cooperation has continued with Russia and the United States as two of the biggest partners in the largest space station built: the International Space Station (ISS). The strength of their cooperation on this project was even more evident when NASA began relying on Russian launch vehicles to service the ISS during the two-year grounding of the shuttle fleet following the 2003 Space Shuttle Columbia disaster.

The Shuttle fleet lost two orbiters and 14 astronauts in two disasters: Challenger in 1986, and Columbia in 2003.[55] While the 1986 loss was mitigated by building the Space Shuttle Endeavour from replacement parts, NASA did not build another orbiter to replace the second loss.[55] NASA's Space Shuttle program had 135 missions when the program ended with the successful landing of the Space Shuttle Atlantis at the Kennedy Space Center on July 21, 2011. The program spanned 30 years with over 300 astronauts sent into space.[56]

Long duration missions to the ISS are referred to as ISS Expeditions. Expedition crew members typically spend approximately six months on the ISS.[65] The initial expedition crew size was three, temporarily decreased to two following the Columbia disaster. Since May 2009, expedition crew size has been six crew members.[66] Crew size is expected to be increased to seven, the number the ISS was designed for, once the Commercial Crew Program becomes operational.[67] The ISS has been continuously occupied for the past 700114000000000000014 years and 7002113000000000000113 days, having exceeded the previous record held by Mir; and has been visited by astronauts and cosmonauts from 15 different nations.[68][69]

Spacewalking NASA astronaut in Earth orbit

The station can be seen from the Earth with the naked eye and, as of 2014, is the largest artificial satellite in Earth orbit with a mass and volume greater than that of any previous space station.[70] The Soyuz spacecraft delivers crew members, stays docked for their half-year long missions and then returns them home. Several uncrewed cargo spacecraft service the ISS, they are the Russian Progress spacecraft which has done so since 2000, the European Automated Transfer Vehicle (ATV) since 2008, the Japanese H-II Transfer Vehicle (HTV) since 2009, the American Dragon spacecraft since 2012, and the American Cygnus spacecraft since 2013. The Space Shuttle, before its retirement, was also used for cargo transfer and would often switch out expedition crew members, although it did not have the capability to remain docked for the duration of their stay. Until another US manned spacecraft is ready, crew members will travel to and from the International Space Station exclusively aboard the Soyuz.[71] The highest number of people occupying the ISS has been thirteen; this occurred three times during the late Shuttle ISS assembly missions.[72]

The ISS program is expected to continue until at least 2020 but may be extended until 2028 or possibly beyond that.[73]

Commercial Resupply Services (2006-present)

The development of the Commercial Resupply Services (CRS) vehicles began in 2006 with the purpose of creating American commercially operated uncrewed cargo vehicles to service the ISS.[74] The development of these vehicles was under a fixed price milestone-based program, meaning that each company that received a funded award had a list of milestones with a dollar value attached to them that they didn't receive until after they had successful completed the milestone.[75] Private companies were also required to have some "skin in the game" which refers raising an unspecified amount of private investment for their proposal.[76]

Commercial Crew Program (2010–present)

The Commercial Crew Development (CCDev) program was initiated in 2010 with the purpose of creating American commercially operated crewed spacecraft capable of delivering at least four crew members to the ISS, staying docked for 180 days and then returning them back to Earth.[82][82] It is hoped that these vehicles could also transport non-NASA customers to private space stations such those planned by Bigelow Aerospace.[83] Like COTS, CCDev is also a fixed price milestone-based developmental program that requires some private investment.[75]

In 2010, NASA announced the winners of the first phase of the program, a total of $50 million was divided among five American companies to foster research and development into human spaceflight concepts and technologies in the private sector. In 2011, the winners of the second phase of the program were announced, $270 million was divided among four companies.[84] In 2012, the winners of the third phase of the program were announced, NASA provided $1.1 billion divided among three companies to further develop their crew transportation systems.[85] The winners of the next round were SpaceX's Dragon (planned to be launched on a Falcon 9), Boeing's CST-100 (to be launched on an Atlas V), and Sierra Nevada's Dream Chaser (to be launched on an Atlas V).[86] NASA will most likely only choose one provider for the Commercial Crew program, this vehicle is expected by NASA to become operational around 2017.[87][88]

The unmanned variant of Dragon is seen approaching the ISS

Computer rendering of CST-100 in orbit

Dream Chaser atmospheric test article

Beyond Low Earth Orbit program (2010–present)

Artist's rendering of the 70 mt variant of SLS launching Orion

For missions beyond low Earth orbit (BLEO), NASA has been directed to develop the Space Launch System (SLS), a Saturn-V class rocket, and the two to six person, beyond low Earth orbit spacecraft, Orion. In February 2010, President Barack Obama's administration proposed eliminating public funds for the Constellation program and shifting greater responsibility of servicing the ISS to private companies.[89] During a speech at the Kennedy Space Center on April 15, 2010, Obama proposed a new heavy-lift vehicle (HLV) to replace the formerly planned Ares V.[90] In his speech, Obama called for a manned mission to an asteroid as soon as 2025, and a manned mission to Mars orbit by the mid-2030s.[90] The NASA Authorization Act of 2010 was passed by Congress and signed into law on October 11, 2010.[91] The act officially canceled the Constellation program.[91]

Orion spacecraft design as of January 2013

The Authorization Act required a newly designed HLV be chosen within 90 days of its passing; the launch vehicle was given the name "Space Launch System". The new law also required the construction of a beyond low earth orbit spacecraft.[92] The Orion spacecraft, which was being developed as part of the Constellation program, was chosen to fulfill this role.[93] The Space Launch System is planned to launch both Orion and other necessary hardware for missions beyond low Earth orbit.[94] The SLS is to be upgraded over time with more powerful versions. The initial capability of SLS is required to be able to lift 70 mt into LEO. It is then planned to be upgraded to 105 mt and then eventually to 130 mt.[93][95]

Exploration Flight Test 1 (EFT-1), an unmanned test flight of Orion's crew module, was launched on December 5, 2014, atop a Delta IV Heavy rocket.[95]Exploration Mission-1 (EM-1) is the unmanned initial launch of SLS that would also send Orion on a circumlunar trajectory, which is planned for 2017.[95] The first manned flight of Orion and SLS, Exploration Mission 2 (EM-2) is to launch between 2019 and 2021; it is a 10- to 14-day mission planned to place a crew of four into Lunar orbit.[95] As of March 2012, the destination for EM-3 and the intermediate focus for this new program is still in-flux.[96]

Unmanned programs

Deep space mission deployed by Shuttle, 1989

More than 1,000 unmanned missions have been designed to explore the Earth and the solar system.[97] Besides exploration, communication satellites have also been launched by NASA.[98] The missions have been launched directly from Earth or from orbiting space shuttles, which could either deploy the satellite itself, or with a rocket stage to take it farther.

The first US unmanned satellite was Explorer 1, which started as an ABMA/JPL project during the early space race. It was launched in January 1958, two months after Sputnik. At the creation of NASA the Explorer project was transferred to this agency and still continues to this day. Its missions have been focusing on the Earth and the Sun, measuring magnetic fields and the solar wind, among other aspects.[99] A more recent Earth mission, not related to the Explorer program, was the Hubble Space Telescope, which as mentioned above was brought into orbit in 1990.[100]

The inner Solar System has been made the goal of at least four unmanned programs. The first was Mariner in the 1960s and 70s, which made multiple visits to Venus and Mars and one to Mercury. Probes launched under the Mariner program were also the first to make a planetary flyby (Mariner 2), to take the first pictures from another planet (Mariner 4), the first planetary orbiter (Mariner 9), and the first to make a gravity assist maneuver (Mariner 10). This is a technique where the satellite takes advantage of the gravity and velocity of planets to reach its destination.[101]

The first successful landing on Mars was made by Viking 1 in 1976. Twenty years later a rover was landed on Mars by Mars Pathfinder.[102]

Outside Mars, Jupiter was first visited by Pioneer 10 in 1973. More than 20 years later Galileo sent a probe into the planet's atmosphere, and became the first spacecraft to orbit the planet.[103]Pioneer 11 became the first spacecraft to visit Saturn in 1979, with Voyager 2 making the first (and so far only) visits to Uranus and Neptune in 1986 and 1989, respectively. The first spacecraft to leave the solar system was Pioneer 10 in 1983. For a time it was the most distant spacecraft, but it has since been surpassed by both Voyager 1 and Voyager 2.[104]

Pioneers 10 and 11 and both Voyager probes carry messages from the Earth to extraterrestrial life.[105][106] A problem with deep space travel is communication. For instance, it takes about 3 hours at present for a radio signal to reach the New Horizons spacecraft at a point more than halfway to Pluto.[107] Contact with Pioneer 10 was lost in 2003. Both Voyager probes continue to operate as they explore the outer boundary between the Solar System and interstellar space.[108]

Artist's concept of NASA's Intelligent Payload Experiment (IPEX) and M-Cubed/COVE-2 satellites ("CubeSats") that were launched as part of the NROL-39 GEMSat mission in December 2013.

On November 26, 2011, NASA's Mars Science Laboratory mission was successfully launched for Mars. Curiosity successfully landed on Mars on August 6, 2012, and subsequently began its search for evidence of past or present life on Mars.[109][110][111]

Recent and planned activities

NASA's ongoing investigations include in-depth surveys of Mars and Saturn and studies of the Earth and the Sun. Other active spacecraft missions are MESSENGER for Mercury, New Horizons (for Jupiter, Pluto, and beyond), and Dawn for the asteroid belt. NASA continued to support in situ exploration beyond the asteroid belt, including Pioneer and Voyager traverses into the unexplored trans-Pluto region, and Gas Giant orbiters Galileo (1989–2003), Cassini (1997–), and Juno (2011–).

On December 4, 2006, NASA announced it was planning a permanent moon base.[113] The goal was to start building the moon base by 2020, and by 2024, have a fully functional base that would allow for crew rotations and in-situ resource utilization. However in 2009, the Augustine Committee found the program to be on a "unsustainable trajectory."[114] In 2010, President Barack Obama halted existing plans, including the Moon base, and directed a generic focus on manned missions to asteroids and Mars, as well as extending support for the International Space Station.[115]

On August 6, 2012, NASA landed the rover Curiosity on Mars. On August 27, 2012, Curiosity transmitted the first pre-recorded message from the surface of Mars back to Earth, made by Administrator Charlie Bolden:

Hello. This is Charlie Bolden, NASA Administrator, speaking to you via the broadcast capabilities of the Curiosity Rover, which is now on the surface of Mars. Since the beginning of time, humankind’s curiosity has led us to constantly seek new life...new possibilities just beyond the horizon. I want to congratulate the men and women of our NASA family as well as our commercial and government partners around the world, for taking us a step beyond to Mars. This is an extraordinary achievement. Landing a rover on Mars is not easy – others have tried – only America has fully succeeded. The investment we are making...the knowledge we hope to gain from our observation and analysis of Gale Crater, will tell us much about the possibility of life on Mars as well as the past and future possibilities for our own planet. Curiosity will bring benefits to Earth and inspire a new generation of scientists and explorers, as it prepares the way for a human mission in the not too distant future. Thank you.[120]

Scientific research

Mars rock, viewed by a rover

Medicine in space

A variety of large-scale medical studies are being conducted in space by the National Space Biomedical Research Institute (NSBRI). Prominent among these is the Advanced Diagnostic Ultrasound in Microgravity Study, in which astronauts (including former ISS Commanders Leroy Chiao and Gennady Padalka) perform ultrasound scans under the guidance of remote experts to diagnose and potentially treat hundreds of medical conditions in space. Usually there is no physician on board the International Space Station, and diagnosis of medical conditions is challenging. Astronauts are susceptible to a variety of health risks including decompression sickness, barotrauma, immunodeficiencies, loss of bone and muscle, orthostatic intolerance due to volume loss, sleep disturbances, and radiation injury. Ultrasound offers a unique opportunity to monitor these conditions in space. This study's techniques are now being applied to cover professional and Olympic sports injuries as well as ultrasound performed by non-expert operators in populations such as medical and high school students. It is anticipated that remote guided ultrasound will have application on Earth in emergency and rural care situations, where access to a trained physician is often rare.[121][122][123]

Ozone depletion

In 1975, NASA was directed by legislation to research and monitor the upper atmosphere. This led to Upper Atmosphere Research Program and later the Earth Observing System (EOS) satellites in the 1990s to monitor ozone depletion.[124] The first comprehensive worldwide measurements were obtained in 1978 with the Nimbus 7 satellite and NASA scientists at the Goddard Institute for Space Studies.[125]

Salt evaporation and energy management

In one of the nation's largest restoration projects, NASA technology helps state and federal government reclaim 15,100 acres (61 km2) of salt evaporation ponds in South San Francisco Bay. Satellite sensors are used by scientists to study the effect of salt evaporation on local ecology.[126]

NASA has started Energy Efficiency and Water Conservation Program as an agency-wide program directed to prevent pollution and reduce energy and water utilization. It helps to ensure that NASA meets its federal stewardship responsibilities for the environment.[127]

Earth science

Plot of orbits of known Potentially Hazardous Asteroids (size over 460 feet (140 m) and passing within 4.7 million miles (7.6×10^6 km) of Earth's orbit) circa 2013 (alternate image).

Understanding of natural and human-induced changes on the global environment is the main objective of NASA's Earth science. NASA currently has more than a dozen Earth science spacecraft/instruments in orbit studying all aspects of the Earth system (oceans, land, atmosphere, biosphere, cryosphere), with several more planned for launch in the next few years.[128]

^Swenson Jr., Loyd S.; Grimwood, James M.; Alexander, Charles C. (1989). "11-4 Shepard's Ride". In Woods, David; Gamble, Chris. This New Ocean: A History of Project Mercury (url). Published as NASA Special Publication-4201 in the NASA History Series (NASA). Retrieved July 14, 2009.

^Swenson Jr., Loyd S.; Grimwood, James M.; Alexander, Charles C. (1989). "13-4 An American in Orbit". In Woods, David; Gamble, Chris. This New Ocean: A History of Project Mercury (url). Published as NASA Special Publication-4201 in the NASA History Series (NASA). Retrieved July 14, 2009.

^"Mercury Manned Flights Summary". NASA. Retrieved October 9, 2011.

^"NASA history, Gagarin". NASA. Retrieved October 9, 2011.

^Barton C. Hacker; James M. Grimwood (December 31, 2002). "10-1 The Last Hurdle". On the Shoulders of Titans: A History of Project Gemini (url). NASA.

^Barton C. Hacker; James M. Grimwood (December 31, 2002). "12-5 Two Weeks in a Spacecraft". On the Shoulders of Titans: A History of Project Gemini. NASA.

^Barton C. Hacker; James M. Grimwood (December 31, 2002). "13-3 An Alternative Target". On the Shoulders of Titans: A History of Project Gemini. NASA.

^John F. Kennedy "Landing a man on the Moon" Address to Congress on YouTube, speech

^Gerstenmaier, William (October 12, 2011). "Statement of William H. Gerstenmaier Associate Administrator for HEO NASA before the Subcommittee on Space and Aeronautics Committee on Science, Space and Technology U. S. House of Representatives". United States House of Representatives. Retrieved August 31, 2012.

^"Memorandum of Understanding Between the National Aeronautics and Space Administration of the United States of America and the Russian Space Agency Concerning Cooperation on the Civil International Space Station". NASA. January 29, 1998. Retrieved April 19, 2009.

^ ab"Moving Forward: Commercial Crew Development Building the Next Era in Spaceflight". Rendezvous. NASA. 2010. pp. 10–17. Retrieved February 14, 2011. Just as in the COTS projects, in the CCDev project we have fixed-price, pay-for-performance milestones," Thorn said. "There’s no extra money invested by NASA if the projects cost more than projected.

Current missions

Space exploration can affect life on Earth by using toxic chemicals to manufacture rockets, and carbon dioxide pumped into the atmosphere during operation of rockets.[143] NASA addressed environmental concerns of its now defunct constellation program in accordance with the National Environmental Policy Act.[144]

Environmental Impact

The percentage of federal budget that NASA has been allocated has been steadily dropping since the Apollo program and as of 2012 the NASA budget is estimated to be 0.48% of the federal budget.[140] In a March 2012 meeting of the United States Senate Science Committee, Neil deGrasse Tyson testified that "Right now, NASA’s annual budget is half a penny on your tax dollar. For twice that—a penny on a dollar—we can transform the country from a sullen, dispirited nation, weary of economic struggle, to one where it has reclaimed its 20th century birthright to dream of tomorrow."[141][142]

NASA's budget has generally been approximately 1% of the federal budget from the early 1970s on, but briefly peaked to approximately 4.41% in 1966 during the Apollo program.[138] Recent public perception of the NASA budget has been shown to be significantly different from reality; a 1997 poll indicated that Americans responded on average that 20% of the federal budget went to NASA.[139]

NASA's budget from 1958 to 2012 as a percentage of federal budget

Budget

Another major facility is Marshall Space Flight Center in Huntsville, Alabama at which the Saturn 5 rocket and Skylab were developed.[137] The JPL, mentioned above, was together with ABMA one of the agencies behind Explorer 1, the first American space mission.

John F. Kennedy Space Center (KSC), is one of the best-known NASA facilities. It has been the launch site for every United States human space flight since 1968. Although such flights are currently on pause, KSC continues to manage and operate unmanned rocket launch facilities for America's civilian space program from three pads at the adjoining Cape Canaveral Air Force Station.

NASA's facilities are research, construction and communication centers to help its missions. Some facilities serve more than one application for historic or administrative reasons. NASA also operates a short-line railroad at the Kennedy Space Center and own special aircraft for instance two of the Space Shuttle orbiter.

The third administrator was James E. Webb (served 1961–1968), appointed by President John F. Kennedy. In order to implement the Apollo program to achieve Kennedy's goal of landing a man on the Moon by 1970, Webb directed major management restructuring and facility expansion, establishing the Houston Manned Spacecraft (Johnson) Center and the Florida Launch Operations (Kennedy) Center.

The first administrator was Dr. T. Keith Glennan, appointed by President Dwight D. Eisenhower; during his term he brought together the disparate projects in space development research in the US.[135]

NASA's administrator is the agency's highest-ranking official and serves as the senior space science adviser to the President of the United States. The agency's administration is located at NASA Headquarters in Washington, DC and provides overall guidance and direction.[133] Except under exceptional circumstances, NASA civil service employees are required to be citizens of the United States.[134]

[131] named the “Joint Group on Pollution Prevention”. The group is working on reduction or elimination of hazardous materials or processes.Defense Contract Management Agency National Space Agency made a partnership with Military Services and [130]

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